Bridge over Nishnabotna River in Crawford County. (Iowa DOT photo)

Bridge over Nishnabotna River in Crawford County. (Iowa DOT photo)

A new report shows 22-percent of Iowa’s rural bridges are “structurally deficient.” That’s the third highest rate in the nation according to the National Transportation Research Group. The report states 4,815 of Iowa’s 21,939 rural bridges are structurally deficient.

Scott Neubauer, bridge maintenance and inspection engineer with the Iowa Department of Transportation, says most of the bridges at issue carry very few vehicles.

“Over 3,800 of them have less than 50 vehicles a day and about 4,500 of them have less than 500 vehicles a day,” Neubauer says.

Most of the old bridges in Iowa deemed structurally deficient have weight restrictions posted. Neubauer says many counties don’t have enough money to fix those bridges and choose to focus on the structures that carry the heavy trucks and traffic volume. “That’s why some of these stay deficient for so long,” Neubauer says. “It’s just on such a low volume road and carries such a small amount of traffic and the traffic it is carrying, the bridge is adequate…and it’s not really a hindrance to anybody, so the county just does the bare minimum to maintain it.”

Neubauer notes the term “structurally deficient” does not necessarily mean the bridge is unsafe. “You know, just because it’s structurally deficient doesn’t mean that it can’t last in that current condition for many years,” Neubauer says. According to the report, only Pennsylvania (25%) and Rhode Island (23%) have higher rates of rural bridges that are structurally deficient.

Neubauer says it’s possible many Iowa counties in the coming years will direct more money toward repairing or replacing old bridges from funds generated by this year’s increase in the state’s gas tax.